That's exactly why. Because silly people see it and go "ooh, it's new and all shiny" and they are willing to overpay for the cheap tech that you can get for half the price in the D600.

Also, in general Nikon and Canon gear is getting seriously more expensive. New Canon 24-70 costs almost twice the old one. Nikon 58/1.4G which looks soft wide open is extremely expensive. And look at the price drops the D800/D600 have had since launch. Everything new is very overpriced, designed to maximise the profits from daft people who MUST be the first to own something.